Traditional patient treatment models in which a patient with a potential problem goes to a medical facility (doctor's office, clinic, or hospital) for examination and treatment have several problems. First, the cost of delivering services in this manner is very high both in terms of monetary outlays and the patient's time. If the patient's complaint is relatively minor, or appears relatively minor to the patient, the patient is likely to forgo examination either because of the inconvenience and/or cost or because the patient cannot obtain a timely appointment with his or her physician. In the case of a patient who is a minor, the supervising parent may not be able to take the time off from work to bring the child to the child's doctor. Furthermore, even for patient's having health insurance, the economic costs are significant.
Second, the symptoms may disappear before the patient has a chance to be examined by his or her doctor. A patient with a heart condition may feel symptoms suggesting a cardiac event such as paroxysmal arrhythmias or, electrocardiographic changes detected during an angina pectoris event or chest pain episode. By the time the patient gets to a doctor and is hooked up to an ECG, the symptoms may have passed leaving the physician with uncertainty as to whether or not a significant heart event occurred.
Third, in many rural areas, a physician may not be available to treat the patient even if the patient can travel some distance to a clinic. Many countries or regions in countries have an acute shortage of medical personnel.
Finally, as the population ages in many of the developed countries, the need for a more efficient mechanism for delivering medical services and information is needed to reduce the economic costs of caring for the elderly. Even developed countries may find the cost of caring for the elderly under the traditional model to be too expensive.
Many systems that attempt to address all or part of these concerns by remote sensing of the patient's condition have been proposed. However, none of these proposed solutions have found widespread acceptance. For example, a number of systems that utilize remote ECG measurements to analyze a cardiac patient's condition have been proposed. These systems include some form of ECG electrodes that are attached to the patient's body and connected to a local processor carried by the patient. The local processor typically includes a transmitter that relays the measurements from the unit worn by the patient to a physician at a remote location. The relay mechanism can utilize a telephone line, either land or cellular, or some form of dedicated transmitter.
One problem with this type of system has to do with the placement of the electrodes on the patient's body. Correct placement of the electrodes is essential to providing useful data to the physician who must view the remotely acquired data. There are two types of systems in this regard. In the first, the electrodes are placed on the patient by the physician or a trained technician in the physician's office. In this case, the placement is ensured; however, the patient is restricted in his or her activities by the permanent placement of the electrodes. Simple tasks such as bathing and sleeping become problematic. Hence, this type of system is best suited for situations in which a cardiac event is expected over a relatively short period of time. In addition, the patient has the system in place for limited periods of time, and hence, the system may not be in place when an event occurs.
In the second type of system, the patient or a caretaker must place the electrodes on the patient's body when physical symptoms indicating that a cardiac event may be occurring are observed by the patient. This type of system relies on training the patient to correctly place the electrodes on his or her body. For many patients this is an unrealistic expectation. Furthermore, even a well-trained patient may have problems with the placement during a perceived cardiac event due to the physiological stress of the event.
While ECG measurements have been the subject of numerous patents, other forms of remote diagnostic instruments have been proposed. For example, systems that implement a stethoscope utilizing a microphone whose output is transmitted to a nurse or doctor who is at a remote location have also been suggested. Again, these systems rely on the correct placement of the microphone on the patient's body.